The Theory of Plate Tectonics

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Vocab

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Plates: The lithosphere is broken into separate sections called plates.
Scientific theory: A well-tested concept that explains a wide range of observations.
Plate tectonics: A geological theory that states that pieces of Earth's lithosphere are in constant slow motion, driven by convection currents (see section 2).
Faults: Faults form where plates have slipped past each other.
Transform boundary: A boundary where two plates slip past each other in the opposite direction.
Divergent boundary: The place where two plates move apart or diverge.
Rift Valley: A deep valley forms along a divergent boundary.
Convergent boundary: When two plates come together a convergent boundary forms.

Outline

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A Theory of Plate Motion:

• Scientific theory that plates move slowly
  • plates
    • broken parts of the lithosphere
    • plates slowly move to a different places
    • moves 2.5 cm. a year
    • can pull apart, slide past, and collide with each other
  • convection currents
    • responsible for movement of plates

Transform Boundary:

• two plates that slip past eachother
  • makes fault
    • like San Andreas fault

Divergent Boundary:

• Two plates move apart
  • makes rift valley
    • African rift valley that runs 3,000 kilometers deep
  • makes trench in water when divergent boundary happens

Convergent Boundary:

• two plates come together
  • causes collision
  • If collision continues, long term affect is a mountain
    • this is how all mountains are formed

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